|Ubuntu 15.10 Beta 2 default desktop|
The recommended way to create a bootable USB stick for Ubuntu is to use Startup Disk Creator. It’s available with your Ubuntu install so you don’t have to install additional packages to get started.
But here’s an alternative to using the official tool that you can use: unetbootin. It’s UI isn’t as nice to look at but it works just as well.
Here’s how to install and run it.
~$ sudo apt-get update
~$ sudo apt-get install unetbootin
The great thing about unetbootin is that it supports creating a bootable USB stick for more than just Ubuntu. Whereas the Startup Disk Creator was designed for Ubuntu and it’s derivatives, unetbootin supports many more Linux distros including (but not limited to) Fedore, OpenSUSE, and Debian.
You can get the list of supported distros from the official site.
|unetbootin UI; not the best looking around but it works|
Using unetbootin is just as easy as using Startup Disk Creator, so it's really a matter of personal preference which tool you want to use. Unetbootin can download the distro you want for you but in case it can’t for whatever reason, you can always download the ISO image yourself and have unetbootin make use of that.
|Creating your USB stick|
I’ve tested with the Ubuntu 15.10 Beta 2 image and it works just fine. You’ll have to download the ISO yourself though since it’s not on the list and selecting Ubuntu daily image failed, at least when I gave it a try.
Unetbootin doesn’t format you USB stick for you and it doesn’t have the option to do so in the UI unlike Ubuntu Startup Disk Creator so you’ll have to format or otherwise delete the contents of your USB stick first to ensure sufficient free space is available.